This invention relates to aqueous polyol-free pearlescing concentrates based on selected surface-active emulsifiers and pearlescent waxes and to their use for the production of pearlescent surface-active compositions.
For centuries, the softly shimmering luster of pearls has held a particular fascination for human beings. It is therefore no wonder that manufacturers of cosmetic preparations endeavour to give their products an attractive, valuable and rich appearance. The first pearlescence used in cosmetics in the middle ages was a pearlescent paste of natural fish scales. At the beginning of the present century, it was discovered that bismuth oxide chlorides were also capable of producing pearlescence. By contrast, pearlescing waxes, particularly of the glycol monofatty acid ester and difatty acid ester type, are of importance in modem cosmetics, being used mainly for the production of pearlescence in hair shampoos and shower gels. An overview of modem pearlescing formulations was published by A. Ansmann and R. Kawa in Parf. Kosm., 75, 578 (1994).
Large numbers of pearlescing compositions and formulations are known from the prior art. For example, DE-A1 35 19 080 (Henkel) describes free-flowing pearlescing concentrates containing 5 to 15% by weight glycol esters, 1 to 6% by weight fatty acid monoethanolamides and 1 to 5% by weight nonionic ethylene oxide adducts with HLB values of 12 to 18. DE-A1 37 24 547 (Henkel) relates to alkanolamide-free pearlescing concentrates which contain 5 to 20% by weight fatty acids and 3 to 10% by weight emulsifiers in addition to glycol fatty acid esters. According to European patents EP-B1 0 376 083 and EP-B1 0 570 398 (Henkel), 15 to 40% by weight glycol fatty acid esters are processed together with 5 to 55% by weight nonionic ampholytic or zwitterionic emulsifiers and 0.1 to 5% by weight or 15 to 40% by weight glycerol to form a pearlescing concentrate. Free-flowing preservative-free pearlescing dispersions containing surfactants (betaines, anionic surfactants, ethoxylates) and glycerol in addition to glycol fatty acid esters are known from DE-A1 42 24 715 (Hoechst). EP-A1 0 684 302 (Th. Goldschmidt) proposes pearlescers containing polyglycerol esters. European patents EP-B1 0 181 773 and EP-B1 0 285 389 (Procter & Gamble) disclose silicone-containing shampoo formulations which contain long-chain acyl compounds as pearlescing waxes. The use of alkyl polyglucosides and selected other surfactants (alkyl sulfates, fatty acid isethionates, betaines and the like) as emulsifiers for the production of pearlescing compositions is known from WO 93/15171 and WO 95/03782 (ICI) and from WO 94/24248 (Henkel Corp.) and WO 95/13863 (SEPPIC). Finally, pearlescent hair conditioners containing selected cationic surfactants are described in EP-A1 0 367 939 (Wella).
Despite this extensive prior art, the problem of providing aqueous pearlescing concentrates, for example as raw materials for the production of hair shampoos, which flow as superconcentrates, even in the absence of polyols (for example glycerol), still exists. Accordingly, the problem addressed by the present invention was to remedy this deficiency.